dictyNews
Electronic Edition
Volume 32, number 14
May 29, 2009

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Abstracts
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PTEN is a mechanosensing signal transducer for myosin II localization
in Dictyostelium cells

Md. Kamruzzaman Pramanik, Miho Iijima, Yoshiaki Iwadate,
Shigehiko Yumura


Genes to Cells, in press

To investigate the role of PTEN in regulation of cortical motile  
activity,
especially in myosin II localization, eGFP-PTEN and mRFP-myosin II
were simultaneously expressed in Dictyostelium cells.  PTEN and
myosin II co-localized at the posterior of migrating cells and furrow
region of dividing cells.  In suspension culture, PTEN knockout (pten–)
cells became multinucleated, and myosin II significantly decreased in
amount at the furrow. During pseudopod retraction and cell aspiration
by microcapillary, PTEN accumulated at the tips of pseudopods and
aspirated lobes prior to the accumulation of myosin II.  In pten– cells,
only a small amount of myosin II accumulated at the retracting
pseudopods and aspirated cell lobes.  PTEN accumulated at the
retracting pseudopods and aspirated lobes even in myosin II null
cells and latrunculin B-treated cells though in reduced amounts,
indicating that PTEN accumulates partially depending on myosin II
and cortical actin.  Accumulation of PTEN prior to myosin II suggests
that PTEN is an upstream component in signaling pathway to localize
myosin II, possibly with mechanosensing signaling loop where
actomyosin-driven contraction further augments accumulation of
PTEN and myosin II by a positive feedback mechanism.


Submitted by: Shigehiko Yumura [[log in to unmask]]
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Learning to get along despite struggling to get by

Elizabeth A Ostrowski* and Gad Shaulsky†

*Department of Ecology and Evolutionary Biology, Rice University,  
Houston,
TX 77005, USA.
†Department of Molecular and Human Genetics, Baylor College of Medicine,
Houston, TX 77030, USA.


Genome Biology 10:218
doi:10.1186/gb-2009-10-5-218

How cooperation can evolve by natural selection is important for
understanding the evolutionary transition from unicellular to  
multicellular
life. Here we review the evolutionary theories for cooperation, with
emphasis on the mechanisms that can favor cooperation and reduce
conflict in multicellular organisms.


Submitted by: Elizabeth Ostrowski [[log in to unmask]]
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[End dictyNews, volume 32, number 14]